#include <REGX52.H>
#include "Delay.h"
unsigned char Key()
{
	unsigned char KeyNumber=0;
	if(P3_1==0){Delay(20);while(P3_1==0);Delay(20);KeyNumber=1;}	
    if(P3_0==0){Delay(20);while(P3_0==0);Delay(20);KeyNumber=2;}	
    if(P3_2==0){Delay(20);while(P3_2==0);Delay(20);KeyNumber=3;}	
    if(P3_3==0){Delay(20);while(P3_3==0);Delay(20);KeyNumber=4;}	
return KeyNumber;
}